In a Z-core sandwich panel, the shear stiffness of the sandwich panel in the weak direction which is perpendicular
to the placement of the Z-cores is much smaller than the bending stiffness because the hollow section between the
two facing plates cannot sustain shear action. Because of this fact, the shear deformation of a Z-core sandwich panel under
bending in the weak direction cannot be ignored. Although the flexural deformation of a Z-core sandwich panel can be
calculated simply from beam theory, the shear deformation is much more difficult to calculate due to the mutual action
between the facing plates and the Z-core stiffener. Considering the contact between the Z-core flanges and the facing
plates, the shear deformation of a typical segment in a Z-core sandwich panel is analyzed based on compatibility conditions.
By using Castigliano’s second theorem, the equations for calculating the deflection caused by shear action of a Zcore
sandwich panel under bending in weak direction are obtained. The overall deflection of the Z-core sandwich panel is
superposed by the deflections caused by flexural and shear actions respectively. The accuracy of the presented equations
for calculating the deflection of a Z-core sandwich panel is finally verified by comparing the predicted results with experimental
results reported in corresponding reference. It is found that the predicted results from the presented equation
agree quite well with experimental results, which shows the reliability and accuracy of the proposed equations.